Engineering the bandgap of a two-dimensional photonic crystal with slender dielectric veins

This study proposes the double-hybrid-rods structure of two-dimensional (2D) photonic crystals of a square lattice. A square dielectric rod connected with slender rectangular dielectric veins on the middle of each side of dielectric square rod. Some specific modes are found to be sensitive to certain structural parameters, such as the length, the dielectric constant and the shift of the position of the veins, etc., and giving rise to a new complete PBG at lower index bands. These results could be understood by the use of band structure point of view. In particular, by carefully adjusting the structural parameters, the band structure of the photonic crystal can be substantially engineered to achieve large bandgaps.